JPS61244982A - Closed loop proportional solenoid valve - Google Patents

Abstract

PURPOSE:To eliminate the necessity for filling oil only for the damping mechanism by providing the damping mechanism at the feedback side of spool valve. CONSTITUTION:A feedback chamber 10 is provided at the feedback endface side of body 4 while a communication path 9 is provided in the center from the squeezed central section of spool valve 5 to the feedback side. Futhermore, said path 9 is communicated to the feedback chamber 10 through a path formed with the sliding outerdiameter section of spool valve 5 and the squeezed section near to the feedback chamber 10. With such arrangement, the necessity for filling oil only for the damping mechanism can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a hydraulic control solenoid valve, and more particularly to an improvement of a closed-loop ratio series solenoid valve for pressure control that is capable of stable control.

[Background of the invention]

A conventional device, as shown in U.S. Pat. No. 4,250,922, is a method in which the inflow flow rate and the discharge flow rate of the valve 1 operating body are determined by the position of a spool valve, and the output pressure is controlled. However, with this structure, the fluid force of the working fluid moves in the direction of the movable axis of the spool valve, changing the control position of the spool valve.

Disturbs the balance between electromagnetic force, feedback force, and spring drag force,
There is a problem that it becomes unstable and the moving parts resonate.

As a method for solving this problem, there is a method described in Japanese Patent Publication No. 49-2217. However, since the movable part of the plunger is a damping mechanism, the dimensions of the plunger that determine the suction force are limited.

In addition, the structure must be such that the plunger movable part is filled with fluid.

[Purpose of the invention]

An object of the present invention is to provide a closed-loop ratio series solenoid valve for hydraulic control that solves the above-mentioned problems and performs stable pressure control.

[Summary of the invention]

In order to solve the above problem, the present invention provides a damping mechanism on the feedback side of the spool valve so that fluid can be easily supplied at all times and the plunger size is not limited.

[Embodiments of the invention] An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 shows an embodiment of a closed-loop ratio series solenoid valve according to the present invention. In the figure, 1 is an inlet port, 2 is an outlet port, and 3 is an exhaust boat, and inside a body 4 that includes these, there is a spool valve 5 that can be slid freely.
is housed, and on the left end side, the end face of a shaft 8, which is attached to a plunger 7 that is pulled to the left in the figure when a current is applied to the coil 6, is in contact with the plunger 7. In addition, the pressure output from the outlet port 2 is transmitted through a feedback passage 9 provided in the spool valve 5 to the sliding inner diameter of the body 4 and the tip of the spool valve 5, which has an outer diameter that is one step narrower than the inner diameter. Feed back chamber 10
be guided by The output pressure led to the feedback chamber 10 acts on the end face of the spool valve and pushes the spool valve 51 in the same direction as the plunger 7, which moves by electromagnetic force.This force is hereinafter referred to as feedback force.A spring resists this force. The position of the spool valve 5 is determined by balancing the 110 forces. Next is the operation based on the above structure,
As mentioned above, the position of the spool valve 5 is determined, which determines the inflow flow rate from the inlet port 1 and the discharge flow rate from the exhaust boat 3. Outputs the pressure. In addition, by changing the current input to the coil 11, the magnetic force is changed, and by moving the position of the spool valve 5, the inflow flow rate and the discharge flow rate are determined as described above, and the current input to the coil 12 from the outlet port 2 is determined. Outputs the corresponding pressure.

Here, when the output pressure decreases due to an increase in the output flow rate from the outlet port 2, the pressure in the feedback chamber 10 to which the output pressure is guided also decreases, and an electromagnetic force is generated at this spool valve 5 position.

The spring drag force and feedback force are not balanced and it moves to the right side of the diagram. This increases the inflow flow rate from the inlet port 1 and decreases the discharge flow rate from the exhaust boat 3, and the pressure increases to a level corresponding to the current input to the coil 12. Therefore, regardless of the change in the output flow rate from outlet port 2, coil 1
Outputs a constant pressure corresponding to the current input to 2.

Normally, the direction of the fluid flowing in from the inlet port 1 is changed by the spool valve 5, so a force due to the fluid flow is applied in the direction of the movable axis of the spool valve 5, and this force disturbs the coupling described in the structural description above. It resonates.

The resonance frequency is dominated by the natural frequency of the one-degree-of-freedom system,
Determined by the weight of the moving part and the spring constant of the spring 11. Normally 3
The frequency is 0 to 100Hz. It is functionally impossible to significantly change these weights and spring constants. According to the present invention, as described above, since the damping mechanism is provided by the diaphragm υ formed by the sliding surface of the body 4 and the tip of the spool valve 5 having a further narrowed outer diameter, it is possible to reach the natural frequency of the one-degree-of-freedom system. Eliminate resonance.

It is possible to control the output pressure stably. Furthermore, according to the present invention, filling of the damping mechanism with oil is always easy and complete. Further, the damping mechanism section can be provided in a small size without limiting the dimensions of the functionally necessary mechanism.

〔Effect of the invention〕

According to the present invention, there is an effect that stable output pressure can be supplied without limiting the dimensions of the functionally necessary mechanism and without filling the damping mechanism with oil.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of one embodiment of the present invention, and FIG. 2 is a detailed vertical cross-sectional view of section P in FIG. 1... Inlet port, 2... Outlet port, 3... Exhaust boat, 4... Body, 5
... Spool valve %6... Coil, 7... Francia, 8... Shaft, 9... Feedback passage, 10... Feedback chamber, 11... Spring.

Claims (1)

[Claims] 1. A core is built inside the coil, a plunger is attached to the side to be attracted by the air, a spring is provided on the axis of a shaft press-fitted into the center of the plunger, and a spring is provided at one end of the shaft to resist electromagnetic force. The spool valve slides inside a body having an inlet port, an outlet port, and an exhaust port, and the center portion thereof is in contact with one end surface of the spool valve, which is tapered one step.The other end surface of the spool valve has the outlet The pressure of the port is fed back to push the spool valve, and the force pushing the spool valve is balanced by the electromagnetic force, the spring force resisting this, and the feedback pressure to determine the position of the spool valve, thereby controlling the pressure. In the closed-loop ratio series solenoid valve, a feedback chamber is provided on the spool valve feedback end face side of the body, and a communication passage is provided along the axis from near the narrower center of the spool valve to the feedback side. A closed-loop ratio ratio solenoid valve characterized in that it is configured to communicate with a feedback chamber through a passage formed by a sliding outer diameter of a spool valve and an outer diameter portion that is narrower at a portion near the feedback.